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Yeshayahu Lifshitz

Bio: Yeshayahu Lifshitz is an academic researcher from Technion – Israel Institute of Technology. The author has contributed to research in topics: Diamond & Chemical vapor deposition. The author has an hindex of 48, co-authored 127 publications receiving 12156 citations. Previous affiliations of Yeshayahu Lifshitz include City University of Hong Kong & University of Freiburg.


Papers
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Journal ArticleDOI
27 Feb 2015-Science
TL;DR: The design and fabrication of a metal-free carbon nanodot–carbon nitride (C3N4) nanocomposite is reported and its impressive performance for photocatalytic solar water splitting is demonstrated.
Abstract: The use of solar energy to produce molecular hydrogen and oxygen (H2 and O2) from overall water splitting is a promising means of renewable energy storage. In the past 40 years, various inorganic and organic systems have been developed as photocatalysts for water splitting driven by visible light. These photocatalysts, however, still suffer from low quantum efficiency and/or poor stability. We report the design and fabrication of a metal-free carbon nanodot-carbon nitride (C3N4) nanocomposite and demonstrate its impressive performance for photocatalytic solar water splitting. We measured quantum efficiencies of 16% for wavelength λ = 420 ± 20 nanometers, 6.29% for λ = 580 ± 15 nanometers, and 4.42% for λ = 600 ± 10 nanometers, and determined an overall solar energy conversion efficiency of 2.0%. The catalyst comprises low-cost, Earth-abundant, environmentally friendly materials and shows excellent stability.

3,553 citations

Journal ArticleDOI
TL;DR: In this paper, a mixture of ammonia-treated carbon nanodots and urea powder was used for 3 h in an alumina crucible to construct a C3N4 matrix.
Abstract: Nanocomposites of carbon nanodots embedded in a C3N4 matrix are prepared by heating a mixture of ammonia-treated carbon nanodots and urea powder at 550 °C for 3 h in an alumina crucible.

609 citations

Journal ArticleDOI
TL;DR: In this paper, the oxide-assisted growth (OAG) technique was proposed for the growth of nanostructured materials. But the OAG technique is not suitable for high-purity silicon nanowires.
Abstract: In this contribution, we outline oxide-assisted growth (OAG) (distinct from the conventional metal-catalytic vapor-liquid-solid (VLS) process) for the growth of nanostructured materials. This synthesis technique, in whichoxides instead of metals play an important role in inducing the nucleation and growth of nanowires, is capable of producing large quantities of high-purity silicon nanowires with a preferential growth direction, uniform size, and long length, without the need for a metal catalyst. The OAG 1D nanomaterials synthesis is complementary to, and coexistent with, the conventional metal-catalyst VLS approach, and can be utilized to produce nanowires from a host of materials other than Si including Ge nanowires, carbon nanowires, silicon and SnO 2 nanoribbons, and Group III-V and II-VI compound semiconductor nanowires.

580 citations

Journal ArticleDOI
TL;DR: La discussion porte sur le depot de couches de carbones type diamant mais on donne aussi des exemples pour d'autres systemes tels que Si, Ge and Ag.
Abstract: A model describing film growth from hyperthermal (\ensuremath{\sim}1--${10}^{3}$ eV) species impinging on substrates is presented. The model involves a shallow subsurface implantation process called ``subplantation,'' energy loss, preferential displacement of atoms with low displacement energy ${\mathit{E}}_{\mathit{d}}$, leaving the high-${\mathit{E}}_{\mathit{d}}$ atoms intact, sputtering of substrate material, and inclusion of a new phase due to incorporation of a high density of interstitials in a host matrix. Epitaxial or preferred orientation may result from the angular dependence of the ${\mathit{E}}_{\mathit{d}}$ and the boundary conditions imposed by the host matrix, i.e., the ``mold'' effect. The discussion focuses on deposition of carbon diamondlike films, but examples of other systems, such as Si, Ge, and Ag, are provided as well. The model is supported by classical-ion-trajectory calculations and experimental data. The calculations probe the role of ion range, local concentration, backscattering coefficient, sputtering yield, and ion-induced damage in film evolution. The experimental data emphasize in situ surface-analysis studies of film evolution. The physical parameters of the deposition process that are treated are as follows: (i) nature of bombarding species (${\mathrm{C}}^{+}$ versus ${\mathrm{C}}^{\mathrm{\ensuremath{-}}}$, ${\mathrm{C}}^{\mathrm{\ensuremath{-}}}$ versus ${\mathrm{C}}_{2}^{\mathrm{\ensuremath{-}}}$, ${\mathrm{C}}_{\mathit{n}}$${\mathrm{H}}_{\mathit{m}}^{+}$, ${\mathrm{Ar}}^{+}$, and ${\mathrm{H}}^{+}$), (ii) ion energy, (iii) type of substrate, and (iv) substrate temperature during deposition.

517 citations


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Journal ArticleDOI
TL;DR: The state of the art, future directions and open questions in Raman spectroscopy of graphene are reviewed, and essential physical processes whose importance has only recently been recognized are described.
Abstract: Raman spectroscopy is an integral part of graphene research. It is used to determine the number and orientation of layers, the quality and types of edge, and the effects of perturbations, such as electric and magnetic fields, strain, doping, disorder and functional groups. This, in turn, provides insight into all sp(2)-bonded carbon allotropes, because graphene is their fundamental building block. Here we review the state of the art, future directions and open questions in Raman spectroscopy of graphene. We describe essential physical processes whose importance has only recently been recognized, such as the various types of resonance at play, and the role of quantum interference. We update all basic concepts and notations, and propose a terminology that is able to describe any result in literature. We finally highlight the potential of Raman spectroscopy for layered materials other than graphene.

5,673 citations

Journal ArticleDOI
TL;DR: In this paper, the authors describe the deposition methods, deposition mechanisms, characterisation methods, electronic structure, gap states, defects, doping, luminescence, field emission, mechanical properties and some applications of diamond-like carbon.
Abstract: Diamond-like carbon (DLC) is a metastable form of amorphous carbon with significant sp3 bonding. DLC is a semiconductor with a high mechanical hardness, chemical inertness, and optical transparency. This review will describe the deposition methods, deposition mechanisms, characterisation methods, electronic structure, gap states, defects, doping, luminescence, field emission, mechanical properties and some applications of DLCs. The films have widespread applications as protective coatings in areas, such as magnetic storage disks, optical windows and micro-electromechanical devices (MEMs).

5,400 citations

Journal ArticleDOI
TL;DR: It is anticipated that this review can stimulate a new research doorway to facilitate the next generation of g-C3N4-based photocatalysts with ameliorated performances by harnessing the outstanding structural, electronic, and optical properties for the development of a sustainable future without environmental detriment.
Abstract: As a fascinating conjugated polymer, graphitic carbon nitride (g-C3N4) has become a new research hotspot and drawn broad interdisciplinary attention as a metal-free and visible-light-responsive photocatalyst in the arena of solar energy conversion and environmental remediation. This is due to its appealing electronic band structure, high physicochemical stability, and “earth-abundant” nature. This critical review summarizes a panorama of the latest progress related to the design and construction of pristine g-C3N4 and g-C3N4-based nanocomposites, including (1) nanoarchitecture design of bare g-C3N4, such as hard and soft templating approaches, supramolecular preorganization assembly, exfoliation, and template-free synthesis routes, (2) functionalization of g-C3N4 at an atomic level (elemental doping) and molecular level (copolymerization), and (3) modification of g-C3N4 with well-matched energy levels of another semiconductor or a metal as a cocatalyst to form heterojunction nanostructures. The constructi...

5,054 citations

Journal ArticleDOI
TL;DR: A detailed overview of the synthesis, properties and applications of nanoparticles exist in different forms NPs are tiny materials having size ranges from 1 to 100nm They can be classified into different classes based on their properties, shapes or sizes.

3,282 citations

PatentDOI
TL;DR: A carbon dioxide storage system includes a container and a conduit attached to the container for introducing or removing a carbon dioxide-containing composition from the container as mentioned in this paper, which is positioned within the container.
Abstract: A carbon dioxide storage system includes a container and a conduit attached to the container for introducing or removing a carbon dioxide-containing composition from the container. A carbon dioxide storage material is positioned within the container. The carbon dioxide-storage material includes a metal-organic framework, which has a sufficient surface area to store at least 10 carbon dioxide molecules per formula unit of the metal-organic framework at a temperature of about 25° C.

2,320 citations